1. Field of the Invention
The present invention is directed to an ultrasound imaging architecture and, more particularly, to a system and method of capturing and processing ultrasound data and generating images therefrom utilizing pixel oriented processing techniques.
2. Description of the Related Art
Ultrasound Imaging has developed into an effective tool for diagnosing a wide variety of disease states and conditions. The market for ultrasound equipment has seen steady growth over the years, fueled by improvements in image quality and the capability to differentiate various types of tissue. Unfortunately, there are still many applications for ultrasound systems where the equipment costs are too high for significant adoption. Examples are application areas such as breast cancer detection, prostate imaging, musculoskeletal imaging, and interventional radiology. In these areas and others, the diagnostic efficacy of ultrasound imaging depends on excellent spatial and contrast resolution for differentiation and identification of various tissue types. These performance capabilities are found only on the more expensive ultrasound systems, which have more extensive processing capabilities.
Ultrasound imaging has always required extensive signal and image processing methods, especially for array systems employing as many as 128 or more transducer elements, each with unique signal processing requirements. The last decade has seen a transition to the improved accuracy and flexibility of digital signal processing in almost all systems except for those at the lowest tiers of the market. This transition has the potential for reducing system costs in the long term, by utilizing highly integrated digital circuitry. Unfortunately, the low manufacturing volumes of ultrasound systems results in substantial overhead and fixed costs for these unique circuits, and thus the transition to digital signal processing has not significantly reduced system cost.
While ultrasound systems have increasingly adopting digital processing technology, their architectures have not changed significantly from their analog counterparts. Almost all current systems on the market use a modular “flow-through” architecture, with signals and data flowing from one module to the next, as shown in FIGS. 1A and 1B. This is a natural method of dealing with the considerable complexity of ultrasound image formation and processing, and allows separate development teams to work somewhat independently on individual modules. FIG. 1A shows the three types of information processing that are typically performed with ultrasound systems—echo image processing, for normal 2D imaging; Doppler processing, for blood velocity measurements; and color flow image processing, for real-time imaging of blood flow.
A major disadvantage of the flow-through architecture is that each module must wait on its input data from the previous module before it can perform its own processing. The module must then deliver its result to the next module. Even within the blocks shown in FIG. 1A, there are many individual processing steps that are performed in series. Since the rate of system processing is determined by the rate of slowest processing function in the chain, all processing blocks must perform at high speed with minimal latencies, so as to not to introduce delays in seeing an image appear on the display as the scanhead is moved.
Another disadvantage of the flow-through architecture is that it makes inefficient use of resources. Most ultrasound exams are performed primarily with 2D echo imaging only, with only occasional use of Doppler blood velocity measurements or color flow imaging. This means that the complex and expensive hardware processing modules needed to perform these functions are sitting idle most of the time, as they cannot be used in other tasks.